“The directive has serious implications for protection of sources,” Germany’s Stern magazine reporter Hans-Martin Tillack said at a debate on press freedom. “Protection of sources is the basis of journalistic work everywhere in the free world.”

The data retention bill, passed in February with implementation tabled for late 2007, obliges EU governments to store information on who called who and who emailed who for at least six months.

But press leaks based on anonymity help to create “critical debate and controversy” in democratic states Mr Tillack explained, praising the Washington Post’s recent role in securing anonymous information on alleged CIA camps in Europe.

The US government eventually found and sacked CIA analyst Mary McCarthy for her part in the revelations.

EU institutions have already used their influence to try and stifle “unfriendly stories” in the past, the Stern writer said, highlighting the European Commission’s crackdown on his own reporting of EU fraud in the past four years.

Belgian police in 2004 seized Mr Tillack’s contact books due to commission allegations that he secured leaks by bribery, with the International Federation of Journalists (IFJ) worried that commission access to Mr Tillack’s papers is being used to scare off future whistleblowers.

IFJ head Aidan White indicated that member states’ powers of surveillance are being extended “with no end in sight” in the post 11 September 2001 “global war on terror.”

The situation stands in contrast to past “classical war” scenarios when some civil rights were suspended for the duration of the conflict only, or to free reporting of terrorism in Northern Ireland in the 1970s and 1980s.

“When will the commission say the global war on terror is over? That when this happens, we’ll take all this back and go back to normal?” he asked the justice commissioner.

Mr Frattini answered by pledging to try and find “the right balance” between security and civil rights but stated that the current terrorist threat is different to what came before.

“Is it possible to compare the Red Brigade or Irish terrorists with the new international terrorism threat? My first answer is no,” he said, adding that he expects broad public support for the EU’s counter-terror campaign.

Journalists should be free to talk to contacts from the EU’s list of terrorist groups, Mr Frattini indicated, so they can “make citizens aware that terrorism is one of the most serious threats to us.”

But reporters should face legal penalties if their actions amount to helping terror organisations do their work.

Mr Frattini promised that access to the new data retention tools will be strictly limited to officials such as public prosecutors.